2014A&A...561A..89A


Query : 2014A&A...561A..89A

2014A&A...561A..89A - Astronomy and Astrophysics, volume 561A, 89-89 (2014/1-1)

Influence of physical galaxy properties on Lyα escape in star-forming galaxies.

ATEK H., KUNTH D., SCHAERER D., MAS-HESSE J.M., HAYES M., OESTLIN G. and KNEIB J.-P.

Abstract (from CDS):

Among the different observational techniques used to select high-redshift galaxies, the hydrogen recombination line Lyman-alpha (Lyα) is of particular interest because it gives access to the measurement of cosmological quantities such as the star formation rate (SFR) of distant galaxy populations. However, interpreting this line and calibrating such observables are still subject to serious uncertainties. In this context, it important to understand the mechanisms responsible for the attenuation of Lyα emission, and under what conditions the Lyα emission line can be used as a reliable star formation diagnostic tool. We used a sample of 24 Lyα emitters at z ∼0.3 with an optical spectroscopic follow-up to calculate the Lyα escape fraction and its dependence upon different physical properties. We also examined the reliability of Lyα as a SFR indicator. We combined these observations with a compilation of Lyα emitters selected at z = 0 - 0.3 from the literature to assemble a larger sample. We confirm that the Lyα escape fraction clearly depends on the dust extinction following the relation fesc(Lyα) = CLyαx10^-0.4 E(B-V) kLyα^ where kLyα ∼6.67 and CLyα = 0.22. However, the correlation does not follow the expected curve for a simple dust attenuation. A higher attenuation can be attributed to a scattering process, while fesc(Lyα) values that are clearly above the continuum extinction curve can be the result of various mechanisms that can lead to an enhancement of the Lyα output. We also observe that the strength of Lyα and the escape fraction appear unrelated to the galaxy metallicity. Regarding the reliability of Lyα as a SFR indicator, we show that the deviation of SFR(Lyα) from the true SFR (as traced by the UV continuum) is a function of the observed SFR(UV), which can be seen as the decrease in fesc(Lyα) with increasing UV luminosity. Moreover, we observe redshift dependence of this relationship, revealing the underlying evolution of fesc(Lyα) with redshift.

Abstract Copyright:

Journal keyword(s): galaxies: starburst - ultraviolet: galaxies - galaxies: star formation

VizieR on-line data: <Available at CDS (J/A+A/561/A89): table1.dat phot/* spect/*>

Simbad objects: 44

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Number of rows : 44
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 ELAIS S1 reg 00 34 44 -43 28.2           ~ 204 0
2 [DSB2008] 23425 EmG 00 37 29.1 -43 38 08           ~ 4 0
3 [DSB2008] 23257 EmG 00 37 54.0 -43 38 28           ~ 3 0
4 [DSB2008] 16998 EmG 00 38 04.930 -43 52 28.50           ~ 5 0
5 [CBH2010] 009.559041-44.243584 AGN 00 38 14.2 -44 14 37           ~ 4 0
6 [DSB2008] 21062 EmG 00 38 39.9 -43 43 21           ~ 4 0
7 2MASX J00393212-4411305 G 00 39 32.1636894768 -44 11 30.383729412           ~ 10 0
8 [DSB2008] 2386 EmG 00 40 01.9 -44 25 44           ~ 2 0
9 [DSB2008] 16921 EmG 00 41 05.6 -43 52 29           ~ 4 0
10 IC 1586 bCG 00 47 56.301 +22 22 22.51   15.0       ~ 74 0
11 Mrk 960 bCG 00 48 35.430 -12 42 59.77   15.5       ~ 105 0
12 Mrk 357 SyG 01 22 40.5874370808 +23 10 14.691256572   15.76 15.40     ~ 92 0
13 CD-28 595 PM* 01 54 50.2703221766 -27 28 35.739139915   12.06 11.51     ~ 130 0
14 IC 214 G 02 14 05.586 +05 10 23.37   14.4       ~ 149 0
15 CPD-69 177 WD* 03 10 31.0195960176 -68 36 03.380768388 10.757 11.413 11.394 11.47 11.558 DA3.0 264 0
16 [DSB2008] 3801 EmG 03 30 56.87 -28 16 47.8           ~ 7 0
17 2dFGRS TGS322Z059 G 03 31 34.68 -28 20 23.0   19.298   18.687   ~ 5 0
18 [CBH2010] 052.962204-28.188999 EmG 03 31 50.929 -28 11 20.40           ~ 9 0
19 [CBH2010] 052.976501-28.238640 EmG 03 31 54.360 -28 14 19.10           ~ 6 0
20 [DSB2008] 7100 EmG 03 31 59.8687199784 -28 09 53.261757252           ~ 6 0
21 [CBH2010] 053.077999-28.222332 SyG 03 32 18.74 -28 13 21.2   20.05   18.99   ~ 7 0
22 [DSB2008] 33311 EmG 03 32 25.1 -27 17 25           ~ 2 0
23 NAME Chandra Deep Field-South reg 03 32 28.0 -27 48 30           ~ 2085 1
24 [CBH2010] 053.174255-28.190306 EmG 03 32 41.821 -28 11 25.10           ~ 5 0
25 CXOCDFS J033256.8-275318 QSO 03 32 56.6570292528 -27 53 16.624989096 20.82 20.5562   19.874 20.2611 ~ 48 0
26 [DSB2008] 1348 EmG 03 32 57.6582082992 -28 23 18.441361896           ~ 7 0
27 [CBH2010] 053.258461-28.357668 EmG 03 33 02.031 -28 21 27.60           ~ 5 0
28 LEDA 750493 GiC 03 33 07.24 -27 44 31.2       17.66   ~ 33 0
29 [CBH2010] 053.359249-27.454334 EmG 03 33 26.220 -27 27 15.60           ~ 5 0
30 SWIRE J033450.70-274346.1 EmG 03 34 50.7018724656 -27 43 45.918537924           ~ 5 0
31 SWIRE J033455.08-274803.6 EmG 03 34 55.1047126776 -27 48 03.572452368           ~ 5 0
32 [DSB2008] 10937 EmG 03 35 08.4 -28 02 43           ~ 2 0
33 HD 289002 * 06 45 13.3725491952 +02 08 14.685250596 10.06 10.62 10.44     B1 259 0
34 Mrk 116 PaG 09 34 02.1 +55 14 25           ~ 1104 1
35 Mrk 33 AG? 10 32 31.956 +54 24 03.53 13.29 13.66 13.13 12.71 12.27 ~ 368 1
36 Mrk 66 Sy2 13 25 53.813 +57 15 16.08   15.0       ~ 77 0
37 [GBM2008] D3-29 G 14 21 51.160 +52 49 51.21           ~ 4 0
38 Mrk 477 Sy2 14 40 38.0960806920 +53 30 15.961505184   16.05 15.03     ~ 317 1
39 NGC 5860 EmG 15 06 33.73 +42 38 29.2   14.2       ~ 84 0
40 NGC 6090 PaG 16 11 40.3 +52 27 21   14.0       ~ 430 2
41 Mrk 499 bCG 16 48 24.1208837112 +48 42 32.756012676   14.6       ~ 48 0
42 ESO 338-4 EmG 19 27 58.338 -41 34 30.81   13.55 13.21 13.14 13.43 ~ 236 1
43 ESO 185-13 AGN 19 45 00.4907671728 -54 15 02.617201080 14.77 14.94 14.68 14.49 14.19 ~ 50 0
44 Feige 110 HS* 23 19 58.3996844256 -05 09 56.171142864 10.360 11.45 11.50 11.970 12.145 sdO8VIIIHe5 636 1

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